transport: Constify the transports vector

Change-Id: I0c874b5d4c97cf781d83bd381d701f770e069f72
Signed-off-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-on: http://openocd.zylin.com/2135
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>

src/jtag/adapter.c

@@ -48,7 +48,7 @@
  */
 
 extern struct jtag_interface *jtag_interface;
-const char *jtag_only[] = { "jtag", NULL };
+const char * const jtag_only[] = { "jtag", NULL };
 
 static int jim_adapter_name(Jim_Interp *interp, int argc, Jim_Obj * const *argv)
 {